Wheels for rolling stock

ABSTRACT

A wheel for rolling stock such as a tractor which comprises a wheel rim carrying a pneumatic tire having an annular tire cavity and a plurality of substantially spherical balls having a relatively high density, a packed layer of the ball partly filling the tire cavity. When the axis of the wheel is positioned horizontally, the wheel can have a gravity center at a lower point than the axis thereof due to the presence of the heavy balls positioned at the bottom portion of the tire cavity.

Uite States atet n 1 Tsuchiya [4 1 Feb. 13., 1973 1 WHEELS FOR ROLLINGSTOCK [76] Inventor: Shozo Tsuchiya, 160-4, Yugashima,

Yugashima-machi, Amagi, Tagatagun, Japan 22 Filed: April 22, 1970 [21]Appl. No.: 30,915

[30] Foreign Application Priority Data July 12, 1969 Japan ..44/66394[52] US. Cl ..l52/330, 301/41 W, 152/330 [51] Int. Cl. ..B60b 19/06 [58]FieldofSearch ..30l/5 BA,4I W; 152/330, l52/330W;46/l55,20l,202,4l

[56] References Cited UNITED STATES PATENTS Herrick ..30l/5 BA 2,884,0394/1959 Hicks ..30l/5 BA 2,909,389 10/1959 Wilbor ..30l/5 BA.

3,230,999 l/l966 Hicks 152/330 3,312,265 4/1967 Turner ..152/330 PrimaryExaminerRichard J. Johnson Att0rneyGeorge B. Oujevolk 5 7] ABSTRACT Awheel for rolling stocksuch as a tractor which comprises a wheel rimcarrying a pneumatic tire having an annular tire cavity and a pluralityof substantially spherical balls having a relatively high density, apacked layer of the ball partly filling the tire cavity. When the axisof the wheel is positioned horizontally, the wheel can have a gravitycenter at a lower point than the axis thereof due to the presence of theheavy balls positioned at the bottom portion of the tire cavi- 1 Claim,2 Drawing Figures WHEELS FOR ROLLING'STOCK BACKGROUND OF THE INVENTIONThe present invention relates to wheels used in various types of rollingstock and more particularly to wheels adapted for use in work rollingstock such as a, tractor, crane car or fork lift.

Rolling stock particularly like a tractor is required to have a lowercenter of gravity than ordinary vehicles such as passenger automobilesin order to travel in a stable state over undulating road surfaces andthe vehicle body must be prevented from being inclined or overturned bya great external force to which the said may be unavoidably subjecteddepending on the type of work which is being performed.

SUMMARY OF THE INVENTION The present invention provides wheelsparticularly adapted to be fitted to a work rolling stock such as atractor. The wheel comprises a wheel rim, a pneumatic tire attached tosaid rim and a plurality of balls partly filling the cavity of thepneumatic tire. Preferably, the balls may be solid, and consist ofmetals having a relatively high density such as steel, lead orlead-containing alloys, and are generally about 1 to 3 cm in diameter.It is desired that the total weight ofthese balls range from a minimumof substantially. increasing the weight of a wheel as a whole to such amaximum that when the axis of the wheel is brought to a substantiallyhorizontal position, the upper surface of the pa'ckedlayer of ballstouches the top of the round cross section of that part of an annulartire cavity which successively faces the ground.

Where a wheel containing such balls is titted to the axle of rollingstock such as tractor, the weight of balls DESCRIPTION OF THE PREFERREDEMBODIMENTS said frame has a front or steering axle connected actson'the insideofthe bottom of the tire cavity facing v the ground,bringing the center of gravity of the wheel to a far lower point thanthe axial center of the axle. When the wheel rotates, the ballsthemselves-also roll and always tend to move towards the lowest positionin the tire cavity, so that a low cente'r of gravity of the wheel is'maintainedeven while it is rotating. Accordingly, a tractor, forexample; which is provided with such wheels has its center of gravityfar lower than when a weight as heavy as the total weight of the ballsis fitted to any-other part thereof, andis prominently improved instability against overturn.

It is accordingly an object of the present invention to provide a wheelfor'rolling stock which has a center of gravity-always brought to alower position than the axis of the axle .of the rolling stock, insofaras it rotates about said axle while it assumes a horizontal orapproximately horizontal position. Another object of the invention is toprovide rolling stock equipped with such wheels. Sincesuch rolling stockhas extremely great resistance to overturn, it can travel very stablyeven on undulating or inclined ground surfaces.

BRIEF DESCRIPTION OF THE DRAWING FIG. I is a side view of a tractorequipped with wheels according to the present invention, with part ofthe wheel tires broken away; and

FIG. 2 is a cross sectional view of the tire portion of the wheels shownin FIG. 1.

to the wheel 16 through conventional steering means and a driving axle22 connected to the output shaft of the engine enclosed in the case 12through various transmission means. To both ends of the steering axle 20and driving axle 22 are fitted steering wheels 24 and driving wheels 26,respectively.

The steering wheels 24 and driving wheels 26 may be I formed ofdifferent construction and/or specification. Since, however, thesewheels 24 and 26 are of substantially the same type in this embodiment,only the driving wheels 26 will now be described. The driving wheel 26comprises a wheel rim and a pneumatic tire 30 fitted to said rim, thecavity 30a of said pneumatic tire 30 being partly filled, as shown inFIG. 2, with numerous balls 32. Said balls 32 preferably consist of asubstantially spherical solid form of metal of relatively high densitysuch as steel, lead or lead-containing alloys. Said balls 32 may beprepared from, for example, a spherical form of lead about 18 mm indiameter and weighing about 40 g. Said balls 32 are partly filled intothe tire cavity 30a in such amounts that the upper surface of a packedlayer of said balls 32 does not touch the top of the circular crosssection of that'part of the tire cavity 30a successively facing theground when the axis ofthe tire 30 is brought to a horizontal position.

It will be apparent that the diameter and amount of balls to be enclosedinto the pneumatic tire may be varied over a wide range depending on thedimensions, specification and other factors of the wheel 26 and variousrequirements for rolling stock which is to be equipped with said wheel26. While the preferable diameter of the balls 32 is not particularlyspecified, it generally ranges from about 5 mm to about 50 mm. I

When the wheel of the present invention rotates about the shaft ofrolling. stock held in a substantially horizontal position, the balls 32received in the tire cavity 30a roll along the inner plane of the tirecavity 30a due to the gravitational force acting thereon and always tendto occupy the lowest part of the tire cavity 30a. Accordingly, thecenter of gravity of the rolling stock provided 'with such a wheel isheld at a considerably lower position than when a weight as heavy as thetotal weight of said balls 32 is attached to any other part of therolling stock. From the standpoint of elevating the rightingcapabilities of rolling stock to regain its original position withrespect to an inclined plane, such a low center of gravity prominentlyassists said rolling stock in travelling over an inclined or undulatingground surface with great stability. Further, the force exerted by theweight of said balls 32 themselves on the inside of said tire cavity 30ais in turn concentrated on the tread of said tire 30 to increase the apressure at said tread portion, thereby more effectively preventing theslip of rolling stock and improving its tractive force.

To confirm the advantages of the wheels of the present invention, therewere conducted tests so as to define a maximum degree of incliriationtobe allowed for rolling stock using said wheels. In these tests anordinary tractor was used having a dead load of about 5,0()O Kg mountedon four wheels having the measure-' ments of 16.9 X 30. The two'wheelson one side of the tractor body were lifted to determine that angle ofinclination atwh ich said tractor body lost its righting capability. Atractor-provided with wheels lacking the aforementioned balls indicateda maximum inclination of 43. On the other hand, a tractor'provided withfour wheelscontaining an equal amount of lead balls (l8 mm in diameter)whose total weight corresponded to 1 percent of' its dead load displayeda maximum inclination of 48. Where the total 'weight of said ballsaccountedfor l percent and percent of the tractors dead load, thetractor showed a-maximum inclination of 55 and 61, respectively. Thesetests prove that the inclusion of a relatively small amount of saidballs in the wheels of a tractor noticeably improves its rightingcapability and that the larger'content of said balls prominentlyincreases the speed at which said tractor "regains its-originalposition.i

The foregoing description relates to the case where the presentinvention was applied to the wheels of a tractor, but the invention isnot limited thereto'lt will be apparent that the invention will offersimilar advantages where it is employed in various types of work rollingstock travelling at a relatively slow speed, for example, a crane car,fork lift or military armored car.

What is claimed is; l. A land vehicle having a plurality of wheels, eachwheel comprising a wheel rim, and an inflated pneumatic tire attached tosaid rim and having an annular air cavity of generally circular crosssection therein, the radius of said rim being approximately one-half ofthe radius of said tire, a'plurality of dense solid spherical ballswithin said cavity and occupying substantially said balls being free toroll and move in said cavity and to occupy only the lowest portionthereof, thereby increasing ground pressure of the tire and lowering thecenter of gravity of said vehicle.

1. A land vehicle having a plurality of wheels, each wheel comprising awheel rim, and an inflated pneumatic tire attached to said rim andhaving an annular air cavity of generally circular cross sectiontherein, the radius of said rim being approximately one-half of theradius of said tire, a plurality of dense solid spherical balls withinsaid cavity and occupying substantially one-half of the vertical depthof said cavity cross-section in the lower ground-engaging portion ofsaid tire only, said balls being made of a metal selected from the groupconsisting of steel, lead, and lead-containing alloys and of a diameterof between 5 mm and 50 mm, said balls being free to roll and move insaid cavity and to occupy only the lowest portion thereof, therebyincreasing ground pressure of the tire and lowering the center ofgravity of said vehicle.